Reactivity with the peripheral myelin glycoprotein P0 in serum from patients with monoclonal IgM gammopathy and polyneuropathy

Abstract

The major glycoprotein P0 from human and bovine peripheral nerves carries the L2/HNK-1 and L3 carbohydrate epitopes and is recognized by serum from patients with IgM gammopathy and polyneuropathy. Only serum from patients with reactivity toward the myelin-associated glycoprotein (MAG) was reactive with P0, while serum that did not react with MAG also did not recognize P0. Furthermore, the neural adhesion molecules L1, N-CAM, and J1 were also recognized by the serum that reacted with MAG, while the L3 carbohydrate-carrying cell adhesion molecule AMOG was not recognized. These observations indicate a restricted specificity in carbohydrate reactivity of IgM paraproteins and implicate yet another and, for the first time, peripheral myelin-specific glycoprotein in the pathogenesis of demyelinating neuropathy.